GLORY OF THE STARS.

New Zealand Herald, Volume LXIV, Issue 19550, 1 February 1927, Page 15

GLORY OF THE STARS.

THE HEAVENS IN FEBRUARY. PLANETS AND CONSTELLATIONS. Br CRUX AUSTRAXIS. The Sun is in the constellation Capricornus until February 18, when he enters Aquarius. His apparent motion is toward the north, decreasing his apparent altitude at noon at Auckland from 70jdeg. on February 1 to 61deg. on the 28th. The Moon will be nearest Mercury on the morning of February 3, Venus on the morning of the 4th, Jupiter on the morning of the 4th, Mars on the evening of the 9th, and Saturn about mid-day of the 25 th. Mercury is an evening star during the month, drawing further away from the Sun until on February 25 he reaches a maximum elongation of 18deg. east. About that time he may be seen low in. the western sky shortly after sunset. He is in lunar conjunction on the morning of the 3rd, and in conjunction with Jupiter about midnight on February 13. Shortly after sunset on that evening, the two planets may bo found close together. Venus and Jupiter. Y T enus is an evening star during the month and is rapidly drawing away from the Sun. She will be a prominent object in the western sky toward the end of the month. She will be in lunar conjunction on the morning of the 4th, and in conjunction with Jupiter'about 2 a.m. on the morning of the 6th. The two planets may be seen close together on the evening or: the sth shortly after sunset. Mars is an evening star during the month but is now very close to the Sun and almost at his greatest distance from the earth, so that he is losing interest as an object of telescopic observation. He will bis in lunar conjunction on the evening of the 9th, being about 6deg. north of the Moon at 6.30 p.m. on that day. Jupiter is still visible in the early evening sky, although now Hearing the "Sun, with which he will be in conjunction on March 1. He will be in lunar conjunction on the morning of the 4th. Saturn is a morning star in Scorpio during the month. He will be in lunar conjunction on the 25th, and may be seen close to the Moon on that morning. The Constellations. The constellations, as given below, may be seen as indicated at 10 p.m. of the Ist, 9 p.m. of the 15th, and 8 p.m. of the 28th of the month. Looking north, Gemini, with its fine pair, Castor apd Pollux, is now well up in the sky. To the west of Gemini, Auriga, with its prominent star Capella, is now setting _ in the north-west - while over Auriga is Taurus, in which the wonderful groups of the Hyades and Pleiades are always objects of interest. Orion is still prominent slightly to the west of the meridian and above Gemini and Auriga. South of his "belt" is the" "sword," a row of fainter stars pointing toward the "belt." The middle star of this row is surrounded with a faint mistiness just perceptible to the naked eye. This is the famous nebula, a mass of gaseous matter which extends over almost the whole constellation. Below, and to the right of the "belt," is a bricbt red star, Betelgeuse, which was the first star to have its diameter measured. It was found, in December, 1920, that this star had a diameter of 240,000,000 miles. It therefore possesses a diameter 260 times that of the sun, and is 17,000,000 times its volume. An idea of its immense size can be gained from the idea that an express train, travelling at the rate of 60 miles an hour, would take over 1430 years to travel round the equator of Betelgeuse. The Companion of Sirius. South of Orion is Canis Major, in which Sirius, the brightest of the fixed stars, shines almost directly overhead. This star is a twin star, the components of which are remarkably dissimilar. The companion star weighs only half as much as Sirius, but gives only 1-30,000 th of its light. Its density is nearly 1000 times that of the earth, and it revolves about its brilliant primary in a little over 49 years. Between Sirius and Gemini is Canis Minor, with Procyon another prominent star. Rising in the east is Leo, whose brightest star, Regulus, forms part of a string of stars in the form of a sickle. Between Gemini and Leo is Cancer, in which the famous star cluster, the Beehive, appears to the naked eye as a large, hazy spot. Over Leo and straggling to the south-east horizon is the constellation of Hydra. Cetus is settling in the west. Over Cetus is Eridanus, the River, which flows in an irregularly meandering stream of stars from near Orion to the south-west horizon, where it ends with a bright star, Achernar, "the last of the river." The Southern Cross is now well up in the south-eastern sky. Below it is the large constellation of Centaurus with its brilliant Pointers, the brightest of which is the nearest neighbour of the solar system. Between the Cross and Sirius overhead is the. large constellation of Argo. the Ship, which is divided into four groups containing a wealth of detail when viewed with optical aid. The Milkv Way is running north and south, a little to the east of the meridian. The Sunspot Cycle. Although, the Sun has always been an object of interest to man, we may regard the discovery of spots on -Hhe Sun as the beginning of that long series of telescopic researches to which we owo our present knowledge of the solar orb. Though records show that spots were noticed long before the invention of the telescope, there is no reason to believe that the nature of the spots so seen, or the fact that they were true solar phenomena, had ever been suspected until the telescope was applied to their observation. And since sunspots are the only markings visible on the Sun's surface, it is to them we owe our present knowledge of the conditions obtaining in the Sun. Sunspots appear on the Sun at irregular and unexpected intervals. At some times there may be as many as a dozen spots visible; at other times the bright globe may be without blemish. Sunspots appear as dark, black blots on the brilliant surface and possess a variety of shapes, although the general tendency is to round or oval forms. A "large spot is generally surrounded by a dusky border or fringe, conforming with the darker centre in outline, and white patches of the disturbed surface clouds arc often heaped up in the vicinity. Sunspots appear dark only by contrast with the greater brilliancy of the solar diri —if visible atone they would appear quite bright. The darkness of spots is a result of their temperature being lower than that of the surrounding surface. A snnspot is a violent eruption of electrical energy on a scale which has no terrestrial counterpart. The appearance of a spot changes rapidly and as the violent storm dies away brijrht. bridges, formed by the cloud-layer which was so rudely torn aside, gradually form across the spot, materially altering its shape in a few hoars, until in the end these clonds •have covered the spot? entirely arid the disturbed area ha- returned to its normal appearance. Small sunspots do riot last very long, bat some of the larger eruptions sometimes persist for three •or four months, and some have been known to live for a year. One of the largest spat's observed in the last 50 years was visible in 1925. At one stage it occupied l-30Gth part .of the Sun's visible hemisphere, possessing an area of 3900 million square miles, which is about 20 times the area of the entire surface of the earth. Nearly 100 years have elapsed since the discovery was made that the. spots, whichaopear on the solar disc are periodic in character. It is now established that there is a well-defined variation in the number of sunspots, the interval between two maxima being about 11J years. The next maximum is. dae'gt the end of this year or early in. 1928. The curve of sunspot frequency rises much more ouick'v from minimum--to■■maximum than it falls again: the rise taking about_ four years, j the fall about seven. There is sometimes ' a double, maximum and generally a slight revival half-war down the descent.